For storage and repair, motor yachts of about 30 to 80 feet in length are typically hauled from the water in slings suspended from wheeled gantry cranes or in cradles riding on marine railways. Larger yachts require marine railways or dry docks. Smaller yachts utilize trailers towable behind vehicles—usually trucks.
Powerboats and yachts above about 25 feet in length typically are stored outdoors on trailers or cradles. On occasion, they are stored on wooden blocks and supports. Small boats below about 20 feet in length are now often stored in warehouses on racks. The small boats are placed in, or removed from, the racks with forklift trucks (“hi-lo's”). Such trucks are inadequate for larger boats and yachts for a variety of reasons.
Since indoor warehousing of a wide variety of other objects up to and including the size of automobiles has become common, there has been some development of more convenient and safer warehousing for small boats. Illustrative of such warehousing is U.S. Pat. No. 6,007,288 wherein the warehouse is equipped with a traveling overhead crane having a specialized cradle to lift a boat. The boat racks comprise frame assemblies to support rack assemblies having cantilever beams to support the boats. While practical for small boats, such a warehousing system is not practical for large powerboats and yachts.
U.S. Pat. No. 3,786,942 discloses an overhead traveling crane for carrying boats in suspended slings. The suspended slings descend from a first frame that is carried by a second frame in direct suspension from the traveling crane. The first frame is movable horizontally and remains with the stored boat in a rack.
U.S. Pat. Pub. No. 2002/0176767 discloses a rotatable forklift that travels on rails into and out of the storage area to place boats in storage racks. This design allows relatively low warehouses with low doors to be used.
Japanese Pat. Pub. No. 2-183055 and No. 2-241891 disclose a relatively low tower for lifting a boat from the water or a trailer and transferring the tower and boat to a second lift where the tower and boat are lifted to a storage location in a rack. The boat is supported on a frame that is moved into, or retrieved from, the storage location.
French Pat. Pub. No. 2552411 discloses an overhead traveling crane with a telescopic retrieval device for lifting boats from underneath and depositing them in racks for storage.
U.S. Pat. No. 4,190,013 discloses an overhead traveling crane with a rotator and a telescopic frame hanging therefrom to lift relatively small boats to storage locations. U.S. Pat. No. 6,162,003 discloses a honeycomb cell-like storage configuration that is particularly directed to sailing yachts with deep keels and substantial draft. The individual boats are supported on individual cradles that, in turn, slide or roll into individual cells.
While suitable for small watercraft storage, the devices of the prior art are not practical for the storage and retrieval of large power yachts weighing many tons and worth hundreds of thousands, and sometimes millions, of dollars.